ansible/lib/ansible/cli/vault.py

# (c) 2014, James Tanner <tanner.jc@gmail.com>
#
# Ansible is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Ansible is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
#
# ansible-vault is a script that encrypts/decrypts YAML files. See
# http://docs.ansible.com/playbooks_vault.html for more details.

from __future__ import (absolute_import, division, print_function)
__metaclass__ = type

import os
import sys

from ansible.cli import CLI
from ansible.errors import AnsibleError, AnsibleOptionsError
from ansible.module_utils._text import to_text, to_bytes
from ansible.parsing.dataloader import DataLoader
from ansible.parsing.vault import VaultEditor

try:
    from __main__ import display
except ImportError:
    from ansible.utils.display import Display
    display = Display()


class VaultCLI(CLI):
    ''' can encrypt any structured data file used by Ansible.
    This can include *group_vars/* or *host_vars/* inventory variables,
    variables loaded by *include_vars* or *vars_files*, or variable files
    passed on the ansible-playbook command line with *-e @file.yml* or *-e @file.json*.
    Role variables and defaults are also included!

    Because Ansible tasks, handlers, and other objects are data, these can also be encrypted with vault.
    If you'd like to not expose what variables you are using, you can keep an individual task file entirely encrypted.

    The password used with vault currently must be the same for all files you wish to use together at the same time.
    '''

    VALID_ACTIONS = ("create", "decrypt", "edit", "encrypt", "encrypt_string", "rekey", "view")

    FROM_STDIN = "stdin"
    FROM_ARGS = "the command line args"
    FROM_PROMPT = "the interactive prompt"

    def __init__(self, args):

        self.b_vault_pass = None
        self.b_new_vault_pass = None
        self.encrypt_string_read_stdin = False
        super(VaultCLI, self).__init__(args)

    def set_action(self):

        super(VaultCLI, self).set_action()

        # options specific to self.actions
        if self.action == "create":
            self.parser.set_usage("usage: %prog create [options] file_name")
        elif self.action == "decrypt":
            self.parser.set_usage("usage: %prog decrypt [options] file_name")
        elif self.action == "edit":
            self.parser.set_usage("usage: %prog edit [options] file_name")
        elif self.action == "view":
            self.parser.set_usage("usage: %prog view [options] file_name")
        elif self.action == "encrypt":
            self.parser.set_usage("usage: %prog encrypt [options] file_name")
        # I have no prefence for either dash or underscore
        elif self.action == "encrypt_string":
            self.parser.add_option('-p', '--prompt', dest='encrypt_string_prompt',
                                   action='store_true',
                                   help="Prompt for the string to encrypt")
            self.parser.add_option('-n', '--name', dest='encrypt_string_names',
                                   action='append',
                                   help="Specify the variable name")
            self.parser.add_option('--stdin-name', dest='encrypt_string_stdin_name',
                                   default=None,
                                   help="Specify the variable name for stdin")
            self.parser.set_usage("usage: %prog encrypt-string [--prompt] [options] string_to_encrypt")
        elif self.action == "rekey":
            self.parser.set_usage("usage: %prog rekey [options] file_name")

    def parse(self):

        self.parser = CLI.base_parser(
            vault_opts=True,
            usage="usage: %%prog [%s] [options] [vaultfile.yml]" % "|".join(self.VALID_ACTIONS),
            desc="encryption/decryption utility for Ansbile data files",
            epilog="\nSee '%s <command> --help' for more information on a specific command.\n\n" % os.path.basename(sys.argv[0])
        )

        self.set_action()

        super(VaultCLI, self).parse()

        display.verbosity = self.options.verbosity

        can_output = ['encrypt', 'decrypt', 'encrypt_string']

        if self.action not in can_output:
            if self.options.output_file:
                raise AnsibleOptionsError("The --output option can be used only with ansible-vault %s" % '/'.join(can_output))
            if len(self.args) == 0:
                raise AnsibleOptionsError("Vault requires at least one filename as a parameter")
        else:
            # This restriction should remain in place until it's possible to
            # load multiple YAML records from a single file, or it's too easy
            # to create an encrypted file that can't be read back in. But in
            # the meanwhile, "cat a b c|ansible-vault encrypt --output x" is
            # a workaround.
            if self.options.output_file and len(self.args) > 1:
                raise AnsibleOptionsError("At most one input file may be used with the --output option")

        if self.action == 'encrypt_string':
            if '-' in self.args or len(self.args) == 0 or self.options.encrypt_string_stdin_name:
                self.encrypt_string_read_stdin = True

            # TODO: prompting from stdin and reading from stdin seem
            #       mutually exclusive, but verify that.
            if self.options.encrypt_string_prompt and self.encrypt_string_read_stdin:
                raise AnsibleOptionsError('The --prompt option is not supported if also reading input from stdin')

    def run(self):

        super(VaultCLI, self).run()
        loader = DataLoader()

        # set default restrictive umask
        old_umask = os.umask(0o077)

        if self.options.vault_password_file:
            # read vault_pass from a file
            self.b_vault_pass = CLI.read_vault_password_file(self.options.vault_password_file, loader)

        if self.options.new_vault_password_file:
            # for rekey only
            self.b_new_vault_pass = CLI.read_vault_password_file(self.options.new_vault_password_file, loader)

        if not self.b_vault_pass or self.options.ask_vault_pass:
            # the 'read' options don't need to ask for password confirmation.
            # 'edit' is read/write, but the decrypt will confirm.
            if self.action in ['decrypt', 'edit', 'view', 'rekey']:
                self.b_vault_pass = self.ask_vault_passwords()
            else:
                self.b_vault_pass = self.ask_new_vault_passwords()

        if not self.b_vault_pass:
            raise AnsibleOptionsError("A password is required to use Ansible's Vault")

        if self.action == 'rekey':
            if not self.b_new_vault_pass:
                self.b_new_vault_pass = self.ask_new_vault_passwords()
            if not self.b_new_vault_pass:
                raise AnsibleOptionsError("A password is required to rekey Ansible's Vault")

        if self.action == 'encrypt_string':
            if self.options.encrypt_string_prompt:
                self.encrypt_string_prompt = True

        self.editor = VaultEditor(self.b_vault_pass)

        self.execute()

        # and restore umask
        os.umask(old_umask)

    def execute_encrypt(self):
        ''' encrypt the supplied file using the provided vault secret '''

        if len(self.args) == 0 and sys.stdin.isatty():
            display.display("Reading plaintext input from stdin", stderr=True)

        for f in self.args or ['-']:
            self.editor.encrypt_file(f, output_file=self.options.output_file)

        if sys.stdout.isatty():
            display.display("Encryption successful", stderr=True)

    def format_ciphertext_yaml(self, b_ciphertext, indent=None, name=None):
        indent = indent or 10

        block_format_var_name = ""
        if name:
            block_format_var_name = "%s: " % name

        block_format_header = "%s!vault |" % block_format_var_name
        lines = []
        vault_ciphertext = to_text(b_ciphertext)

        lines.append(block_format_header)
        for line in vault_ciphertext.splitlines():
            lines.append('%s%s' % (' ' * indent, line))

        yaml_ciphertext = '\n'.join(lines)
        return yaml_ciphertext

    def execute_encrypt_string(self):
        ''' encrypt the supplied string using the provided vault secret '''
        b_plaintext = None

        # Holds tuples (the_text, the_source_of_the_string, the variable name if its provided).
        b_plaintext_list = []

        # remove the non-option '-' arg (used to indicate 'read from stdin') from the candidate args so
        # we don't add it to the plaintext list
        args = [x for x in self.args if x != '-']

        # We can prompt and read input, or read from stdin, but not both.
        if self.options.encrypt_string_prompt:
            msg = "String to encrypt: "

            name = None
            name_prompt_response = display.prompt('Variable name (enter for no name): ')

            # TODO: enforce var naming rules?
            if name_prompt_response != "":
                name = name_prompt_response

            # could use private=True for shadowed input if useful
            prompt_response = display.prompt(msg)

            if prompt_response == '':
                raise AnsibleOptionsError('The plaintext provided from the prompt was empty, not encrypting')

            b_plaintext = to_bytes(prompt_response)
            b_plaintext_list.append((b_plaintext, self.FROM_PROMPT, name))

        # read from stdin
        if self.encrypt_string_read_stdin:
            if sys.stdout.isatty():
                display.display("Reading plaintext input from stdin. (ctrl-d to end input)", stderr=True)

            stdin_text = sys.stdin.read()
            if stdin_text == '':
                raise AnsibleOptionsError('stdin was empty, not encrypting')

            b_plaintext = to_bytes(stdin_text)

            # defaults to None
            name = self.options.encrypt_string_stdin_name
            b_plaintext_list.append((b_plaintext, self.FROM_STDIN, name))

        # use any leftover args as strings to encrypt
        # Try to match args up to --name options
        if hasattr(self.options, 'encrypt_string_names') and self.options.encrypt_string_names:
            name_and_text_list = list(zip(self.options.encrypt_string_names, args))

            # Some but not enough --name's to name each var
            if len(args) > len(name_and_text_list):
                # Trying to avoid ever showing the plaintext in the output, so this warning is vague to avoid that.
                display.display('The number of --name options do not match the number of args.',
                                stderr=True)
                display.display('The last named variable will be "%s". The rest will not have names.' % self.options.encrypt_string_names[-1],
                                stderr=True)

            # Add the rest of the args without specifying a name
            for extra_arg in args[len(name_and_text_list):]:
                name_and_text_list.append((None, extra_arg))

        # if no --names are provided, just use the args without a name.
        else:
            name_and_text_list = [(None, x) for x in args]

        # Convert the plaintext text objects to bytestrings and collect
        for name_and_text in name_and_text_list:
            name, plaintext = name_and_text

            if plaintext == '':
                raise AnsibleOptionsError('The plaintext provided from the command line args was empty, not encrypting')

            b_plaintext = to_bytes(plaintext)
            b_plaintext_list.append((b_plaintext, self.FROM_ARGS, name))

        # Format the encrypted strings and any corresponding stderr output
        outputs = self._format_output_vault_strings(b_plaintext_list)

        for output in outputs:
            err = output.get('err', None)
            out = output.get('out', '')
            if err:
                sys.stderr.write(err)
            print(out)

        if sys.stdout.isatty():
            display.display("Encryption successful", stderr=True)

        # TODO: offer block or string ala eyaml

    def _format_output_vault_strings(self, b_plaintext_list):
        # If we are only showing one item in the output, we don't need to included commented
        # delimiters in the text
        show_delimiter = False
        if len(b_plaintext_list) > 1:
            show_delimiter = True

        # list of dicts {'out': '', 'err': ''}
        output = []

        # Encrypt the plaintext, and format it into a yaml block that can be pasted into a playbook.
        # For more than one input, show some differentiating info in the stderr output so we can tell them
        # apart. If we have a var name, we include that in the yaml
        for index, b_plaintext_info in enumerate(b_plaintext_list):
            # (the text itself, which input it came from, its name)
            b_plaintext, src, name = b_plaintext_info
            b_ciphertext = self.editor.encrypt_bytes(b_plaintext)

            # block formatting
            yaml_text = self.format_ciphertext_yaml(b_ciphertext, name=name)

            err_msg = None
            if show_delimiter:
                human_index = index + 1
                if name:
                    err_msg = '# The encrypted version of variable ("%s", the string #%d from %s).\n' % (name, human_index, src)
                else:
                    err_msg = '# The encrypted version of the string #%d from %s.)\n' % (human_index, src)
            output.append({'out': yaml_text, 'err': err_msg})

        return output

    def execute_decrypt(self):
        ''' decrypt the supplied file using the provided vault secret '''

        if len(self.args) == 0 and sys.stdin.isatty():
            display.display("Reading ciphertext input from stdin", stderr=True)

        for f in self.args or ['-']:
            self.editor.decrypt_file(f, output_file=self.options.output_file)

        if sys.stdout.isatty():
            display.display("Decryption successful", stderr=True)

    def execute_create(self):
        ''' create and open a file in an editor that will be encryped with the provided vault secret when closed'''

        if len(self.args) > 1:
            raise AnsibleOptionsError("ansible-vault create can take only one filename argument")

        self.editor.create_file(self.args[0])

    def execute_edit(self):
        ''' open and decrypt an existing vaulted file in an editor, that will be encryped again when closed'''
        for f in self.args:
            self.editor.edit_file(f)

    def execute_view(self):
        ''' open, decrypt and view an existing vaulted file using a pager using the supplied vault secret '''

        for f in self.args:
            # Note: vault should return byte strings because it could encrypt
            # and decrypt binary files.  We are responsible for changing it to
            # unicode here because we are displaying it and therefore can make
            # the decision that the display doesn't have to be precisely what
            # the input was (leave that to decrypt instead)
            self.pager(to_text(self.editor.plaintext(f)))

    def execute_rekey(self):
        ''' re-encrypt a vaulted file with a new secret, the previous secret is required '''
        for f in self.args:
            if not (os.path.isfile(f)):
                raise AnsibleError(f + " does not exist")

        for f in self.args:
            self.editor.rekey_file(f, self.b_new_vault_pass)

        display.display("Rekey successful", stderr=True)